pixi.js用移動平均フィルタ

MovingAverageFilter.ts

class MovingAverageFilter extends PIXI.AbstractFilter {
  static fragmentSrc(size: number, width: number, height: number, direction: string) {
    return `
      precision lowp float;
      varying vec2 vTextureCoord;
      varying vec4 vColor;
      uniform sampler2D uSampler;
      void main(void)
      {
        gl_FragColor = vec4(0.0);
        for (int i = 0; i < ${size}; i++) {
          float offset = float(i - ${size} / 2) / float(${(direction === 'x') ? width : height});
          gl_FragColor += texture2D(uSampler, vec2(vTextureCoord.s${(direction === 'x') ? ' + offset' : ''}, vTextureCoord.t${(direction === 'y') ? ' + offset' : ''})) / float(${size});
        }
      }
    `;
  };
  
  xFilter: PIXI.AbstractFilter;
  yFilter: PIXI.AbstractFilter;
  constructor(size: number, width: number, height: number) {
    super();
    this.xFilter = new PIXI.AbstractFilter(null, MovingAverageFilter.fragmentSrc(size, width, height, 'x'));
    this.yFilter = new PIXI.AbstractFilter(null, MovingAverageFilter.fragmentSrc(size, width, height, 'y'));
  }
  
  applyFilter(renderer: PIXI.WebGLRenderer, input: PIXI.RenderTarget, output: PIXI.RenderTarget) {
    const renderTarget = renderer.filterManager.getRenderTarget(true);
    this.xFilter.applyFilter(renderer, input, renderTarget);
    this.yFilter.applyFilter(renderer, renderTarget, output);
    (<any>renderer.filterManager).returnRenderTarget(renderTarget);
  }
}